Page 121 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma
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                                Internet-based tapering of OCS in severe asthma
For research purposes the patients in the conventional management group were asked to enter their daily dose of corticosteroids in the study website, and for safety reasons, they also registered symptoms and lung function, which were accessible to the study nurse only.
Randomization and masking
Randomization was stratified for study centre and initial oral corticosteroid dose (lower or higher than 10 mg prednisone equivalent/day). Patients were randomized with the use of a computer random number generator and remained on the same allocation throughout the study. The treatment assignments were unblinded after randomization to allow monthly corticosteroid dose adjustments according to conventional treatment by the physician, or weekly adjustments according to the internet algorithm.
Outcome measures
The primary outcomes were cumulative sparing of oral corticosteroids (actual cumulative dose minus the expected cumulative dose), and (equivalence in) ACQ and AQLQ. Secondary outcomes were global satisfaction scale, and (equivalence in) FEV1, number of exacerbations and days of hospitalisation. The actual cumulative dose was calculated from the doses registered daily on the website, and the expected cumulative dose was extrapolated from the daily dose at study entry. An exacerbation was defined as a decrease in morning FEV1 of at least 10% compared to mean FEV1 from the week before, or a respiratory event requiring an increase in prednisone equivalent of at least 10 mg/day, or a course of antibiotics, with or without hospitalization.
Newly diagnosed severe adverse effects of corticosteroid use during the study were documented for safety reasons.
Statistical Analysis
The sample size was based on demonstrating equivalence in asthma control between the two groups based on ACQ as the primary outcome measure. The minimal clinically important change in ACQ has been shown to be 0.5 [24]. A sample size of 50 patients per group was enough to detect of a difference of 0.39 points or greater in ACQ between the two groups (α=0.05 2-sided, β=0.20 1 sided).
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